public void ImageWaterMarkText(string filename, ImageFormat format)        {            Image originalImage = Image.FromFile(filename);            Graphics g = Graphics.FromImage(originalImage);                        Font drawFont = new Font("Arial", 12, FontStyle.Regular, GraphicsUnit.Pixel);
　　　　　　　　　　 //找到图片旋转中点                                    float xpos = originalImage.Width > originalImage.Height ? originalImage.Width -  originalImage.Height/ 2 : originalImage.Width / 2;            float ypos = originalImage.Width > originalImage.Height ? originalImage.Height / 2 : originalImage.Height - originalImage.Width / 2;            var triggleLeg = (originalImage.Width > originalImage.Height ? originalImage.Height : originalImage.Width) / 3;            ar gPath = new GraphicsPath();            gPath.AddLine(originalImage.Width - triggleLeg, originalImage.Height, originalImage.Width, originalImage.Height - triggleLeg);            gPath.AddLine(originalImage.Width, originalImage.Height - triggleLeg, originalImage.Width, originalImage.Height);            gPath.AddLine(originalImage.Width, originalImage.Height, originalImage.Width - triggleLeg, originalImage.Height);            g.FillPath(new SolidBrush(Color.FromArgb(120, Color.Black)), gPath);　　　　　　　　　　　　            g.TranslateTransform(xpos, ypos);            g.RotateTransform(-45);            SizeF crSize;            string watermarkText;            
            watermarkText = "测试文字";            crSize = g.MeasureString("Chine LianTong", drawFont);                        g.DrawString(watermarkText, drawFont, new SolidBrush(Color.Red), -crSize.Width / 2, 250);            watermarkText = DateTime.Now.ToString("Current: yyyy-MM-dd HH:mm");            g.DrawString(watermarkText, drawFont, new SolidBrush(Color.Red), -crSize.Width / 2, 250 + crSize.Height + 5);            g.Dispose();            MemoryStream stream = new MemoryStream();            originalImage.Save(stream, format);            originalImage.Dispose();            Image img = Image.FromStream(stream);            img.Save(filename);            img.Dispose();                    }